Re: [PATCH v7 6/9] leds: st1202: fix brightness having no effect while pattern mode is active

On Thu, 2 Jul 2026, [email protected] wrote:

> New issues:
> - [Medium] The return value of `st1202_pwm_pattern_write` is ignored, resulting in missing error handling and I2C error log spam.
> 
> Pre-existing issues:
> - [High] The driver assigns a sleeping function to the LED classdev `.brightness_set` callback, violating the atomic context constraint and exacerbating schedule-while-atomic bugs.
> - [High] Per-channel pattern operations incorrectly overwrite global hardware state, breaking independent channel operation for all other active LEDs.
> - [High] `st1202_led_pattern_set` does not scale the 8-bit brightness values to the 12-bit PWM register scale, resulting in extremely dim patterns.
> - [High] Device node references fetched during `for_each_available_child_of_node_scoped` are not properly acquired, resulting in Use-After-Free when they are accessed later during LED registration.

The comment about the ignored return value of st1202_pwm_pattern_write()
was also raised in the v6 review and addressed in the response to that
review. This is intentional: a transient I2C error on one slot does not
guarantee subsequent writes will also fail. Breaking early would leave
remaining PWM slots unwritten unnecessarily, putting the channel in a
partially updated state. brightness_set() is a void callback and cannot
propagate errors regardless, and st1202_write_reg() already logs each
individual failure via dev_err().

The remaining comments are pre-existing issues outside the scope of
this patch and will be addressed in a follow-up submission.

--
Manuel Fombuena